Q15 of 99 Page 269

In a trapezium, the length of each slant sides is 10 cm. and the length of parallel sides are 5 cm. and 17 cm. respectively. Let us write by calculating area of filed in shape of trapezium and its diagonal.

Given, In a trapezium, the length of each slant sides is 10 cm. and the length of parallel sides are 5 cm. and 17 cm. respectively.


According to the figure two right angled triangles are formed.


In ∆AEC,


⟹ AC2=AE2+CE2 -------(i)


⟹ CE = FD


And 17 = CE +FD +EF


⟹ 17 = 2CE + 5


⟹ 2CE = 12


⟹ CE = 6cm


∴ 102 = AE2 + 62


⟹ AE2= 100 – 36


⟹ AE2= 64


⟹ AE = 8cm


Hence, area of the trapezium =×(5+17)×8


= 88 sq. cm.


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